1. Field of the Invention
The field of the present invention is fail-safe systems for a throttle valve controller for controlling the opening and closing of a throttle valve in an internal combustion engine through a motor.
2. Description of the Prior Art
In the prior art throttle valve controller used in a traction control system or an auto-cruise system, a throttle valve is connected to a motor and driven for opening and closing, or the throttle valve is connected to the motor through a lost motion mechanism and driven for opening and closing, in order to control the output torque from an internal combustion engine.
In such a throttle valve controller, however, if a sticking occurs due to any cause when the throttle valve is driven toward an opened side, the throttle valve may be suddenly brought to an open position by a spring force in a system including the lost motion mechanism interposed between the throttle valve and the motor, or by a driving force of the motor in a system which the throttle valve is connected directly to the motor. This may result in a sudden increase in the output torque from the internal combustion engine.